WO2013084362A1

WO2013084362A1 - Magnetic bearing

Info

Publication number: WO2013084362A1
Application number: PCT/JP2011/078605
Authority: WO
Inventors: 筒井　幸雄; 大戸　基道
Original assignee: 株式会社安川電機
Priority date: 2011-12-09
Filing date: 2011-12-09
Publication date: 2013-06-13
Also published as: CN203879931U

Abstract

This magnetic bearing (10) is provided with electromagnets (11) which include electromagnet cores (13) and coils (14) and permanent magnets (12) which, together with the electromagnets, support without contact a rotating shaft portion (21) by a magnetic attraction force. The electromagnet cores have magnetic resistance change sections (40) disposed in paths through which magnetic fields generated from the coils of the electromagnets pass. The permanent magnets are disposed at portions corresponding to the magnetic resistance change sections of the electromagnet cores. This is in order to prevent magnetic fields generated from the permanent magnets from passing through the magnetic resistance change sections.

Description

Magnetic bearing

The present invention relates to a magnetic bearing, and more particularly, to a magnetic bearing provided with an electromagnet and a permanent magnet.

Conventionally, a magnetic bearing provided with an electromagnet and a permanent magnet is known. Such a magnetic bearing is disclosed, for example, in JP-A-11-101235.

Japanese Patent Application Laid-Open No. 11-101235 discloses a magnetic bearing including an electromagnet made of an electromagnetic steel sheet laminate (electromagnet core) around which an exciting coil is wound, and a permanent magnet attached to the electromagnetic steel sheet laminate. ing. In this magnetic bearing, both the electromagnet and the permanent magnet generate a magnetic field in a plane extending along the axial direction of the rotating shaft (rotating shaft portion), thereby making the rotating shaft non-contact in the radial direction by magnetic attraction. It is configured to support. In this magnetic bearing, a permanent magnet is arranged so as to intersect with a magnetic circuit constituted by a magnetic field generated from an electromagnet.

JP-A-11-101235

However, in the magnetic bearing disclosed in Japanese Patent Application Laid-Open No. 11-101235, the permanent magnet is disposed so as to intersect the magnetic circuit constituted by the magnetic field generated from the electromagnet, so that the magnetic field generated from the electromagnet is permanent. The permanent magnet may be applied in a direction opposite to the magnetized direction of the magnet. For this reason, there is a problem that irreversible demagnetization of the permanent magnet is likely to occur.

The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a magnetic bearing capable of suppressing the occurrence of irreversible demagnetization of a permanent magnet. That is.

In order to achieve the above object, a magnetic bearing according to one aspect of the present invention includes an electromagnet including an electromagnet core and a coil, and a permanent magnet that is attached to the electromagnet core and supports the rotating shaft portion in a non-contact manner together with the electromagnet by magnetic attraction. The electromagnet core has a magnetoresistive change portion arranged in a path through which the magnetic field generated from the coil of the electromagnet passes, and the permanent magnet passes the magnetoresistive change portion generated by the permanent magnet. In order to avoid this, the electromagnet core is disposed at a portion corresponding to the magnetoresistance change portion.

In the magnetic bearing according to one aspect of the present invention, as described above, the electromagnet core is provided with the magnetoresistance change portion arranged in the path through which the magnetic field generated from the electromagnet coil passes, and the magnetic field generated from the permanent magnet is magnetic. The permanent magnet is disposed in a portion corresponding to the magnetoresistance change portion of the electromagnet core so as not to pass through the resistance change portion. Accordingly, the magnetic field generated from the coil passes through the magnetoresistive change portion without passing through the permanent magnet to form a magnetic circuit, so that the magnetic circuit formed by the magnetic field generated from the coil intersects with the permanent magnet. There is nothing. As a result, since the magnetic field generated from the coil is not applied to the permanent magnet in the direction opposite to the magnetization direction of the permanent magnet, the occurrence of irreversible demagnetization of the permanent magnet can be suppressed.

It is typical sectional drawing along the axial direction of the magnetic bearing by 1st Embodiment of this invention. It is the figure which showed the whole structure of the magnetic bearing by 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the flow of the magnetic field generated from the electromagnet and permanent magnet of the magnetic bearing by 1st Embodiment of this invention. It is the figure which showed the whole structure of the magnetic bearing by 2nd Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 1st modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 2nd modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 3rd modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 4th modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 5th modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 6th modification of 1st Embodiment of this invention. It is the elements on larger scale for demonstrating the structure of the magnetic bearing by the 7th modification of 1st Embodiment of this invention. It is typical sectional drawing along the axial direction of the magnetic bearing by the 8th modification of 1st Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the configuration of the magnetic bearing 10 according to the first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, a pair of magnetic bearings 10 are provided on both sides in the axial direction (axial direction: direction in which the rotating shaft 21 extends) of the motor 20 having the rotating shaft 21. Each of the pair of magnetic bearings 10 is along a straight line extending radially from the rotation center O of the rotation shaft 21 (see FIG. 2) in the radial direction (radial direction: plane orthogonal to the rotation shaft 21) with respect to the rotation shaft 21. ) In a predetermined direction (a gap 30 having a gap length L1 (see FIG. 3)). The rotating shaft 21 is an example of the “rotating shaft portion” in the present invention.

Further, as shown in FIG. 2, the magnetic bearing 10 includes an electromagnet 11 and a permanent magnet 12. Both the electromagnet 11 and the permanent magnet 12 generate a magnetic field (see the one-dot chain line and the two-dot chain line in FIG. 3) in a plane orthogonal to the rotation shaft 21 and extending in the radial direction (radial direction). The rotary shaft 21 is configured to be supported in a non-contact manner in the radial direction by force. The electromagnet 11 includes an electromagnet core 13 made of a plurality of electromagnetic steel plates (see FIG. 1) stacked in the axial direction (axial direction), and a coil 14 wound around a first portion 16a (to be described later) of the electromagnet core 13. It is comprised so that it may contain. The permanent magnet 12 is composed of a rare earth magnet or a ferrite magnet. Here, unlike the electromagnet 11, the permanent magnet 12 does not require a current to flow in order to generate a magnetic field. Therefore, in the first embodiment in which the rotating shaft 21 is supported using both the electromagnet 11 and the permanent magnet 12, the power consumption can be reduced unlike the case where the rotating shaft 21 is supported using only the electromagnet 11. It is.

As shown in FIG. 2, the electromagnet core 13 surrounds the outer peripheral surface of the rotating shaft 21 in a circumferential shape and is arranged in four substantially U-shapes arranged adjacent to each other in the circumferential direction (the rotating direction of the rotating shaft 21). The part 15 is comprised. These four substantially U-shaped portions 15 are arranged so as to sandwich the rotating shaft 21 from both sides in the vertical direction and the horizontal direction. That is, a pair of substantially U-shaped portions 15 are provided on both sides of the rotating shaft 21 in the vertical direction, and a pair is also provided on both sides of the rotating shaft 21 in the left-right direction.

Here, in the first embodiment, as shown in FIG. 2, each of the four substantially U-shaped portions 15 constituting the electromagnet core 13 has a gap length L2 of about several hundred μm (see FIG. 3). A void 40 is provided. And the permanent magnet 12 is arrange | positioned in the part corresponding to each space | gap 40 of these four substantially U-shaped parts 15. FIG. The air gap 40 is an example of the “magnetic resistance changing portion” in the present invention.

As shown in FIGS. 2 and 3, the gap 40 is provided in the vicinity of the central portion of the substantially U-shaped portion 15 in the circumferential direction so as to separate the substantially U-shaped portion 15 in the circumferential direction. Specifically, the gap 40 is in a direction orthogonal to the direction in which the magnetic field generated from the coil 14 (see the dashed line in FIG. 3) passes through the gap 40 in the vicinity of the central portion in the circumferential direction of the substantially U-shaped portion 15. It is formed so as to extend along (radial direction). As a result, the substantially U-shaped portion 15 is completely separated into a pair of substantially L-shaped portions 16 that face each other with the gap 40 therebetween. Here, the end faces facing each other through the gap 40 of the pair of substantially L-shaped portions 16 are formed in parallel to each other. That is, the air gap 40 extends along the radial direction so that the gap length L2 (see FIG. 3) is equal between the rotating shaft 21 side and the permanent magnet 12 side. The substantially L-shaped portion 16 is an example of the “core portion” in the present invention.

2 and 3, the pair of substantially L-shaped portions 16 are disposed so as to face each other with the gap 40 interposed therebetween. The pair of substantially L-shaped portions 16 includes a first portion 16a extending along the radial direction and a gap 40 along the circumferential direction from the end of the first portion 16a opposite to the rotating shaft 21. And a second portion 16b extending to the side. The coil 14 is wound around the first portion 16a. Moreover, the flat surface 16c is provided in the surface on the opposite side to the rotating shaft 21 of the 2nd part 16b. And the plate-shaped permanent magnet 12 which has thickness t1 (refer FIG. 3) is arrange | positioned on this flat surface 16c.

As shown in FIG. 3, the permanent magnet 12 is disposed across two flat surfaces 16 c of a pair of substantially L-shaped portions 16 constituting the substantially U-shaped portion 15 of the electromagnet core 13. Further, the vicinity of the surface 12a on the side of the pair of substantially L-shaped portions 16 of the permanent magnet 12 is magnetized so as to have different polarities (N polarity or S polarity) on one side and the other side. Further, the vicinity of the surface 12b of the permanent magnet 12 on the side opposite to the pair of substantially L-shaped portions 16 has a polarity opposite to the vicinity of the surface 12a on the side of the pair of substantially L-shaped portions 16 of the permanent magnet 12. Is so magnetized.

Specifically, as shown in FIG. 3, in the region near the surface 12a on the substantially L-shaped portion 16 side of the permanent magnet 12, the left region has S polarity and the right region has N polarity. Is so magnetized. Further, the region in the vicinity of the surface 12b opposite to the substantially L-shaped portion 16 of the permanent magnet 12 is magnetized so that the left region has N polarity and the right region has S polarity. . The surface 12 b of the permanent magnet 12 opposite to the substantially L-shaped portion 16 is covered with a block-like or plate-like yoke 17. The yoke 17 is formed in a plate shape having a thickness t2 (see FIG. 3) smaller than the thickness t1 (see FIG. 3) of the permanent magnet 12. Further, the yoke 17 and the permanent magnet 12 are bonded by an adhesive or the like.

Here, in the first embodiment, as shown in FIG. 3, the gap length L <b> 2 of the air gap 40 is set to be smaller than the thickness t <b> 1 of the permanent magnet 12. As a result, the magnetic field generated from the coil 14 (see the alternate long and short dash line in FIG. 3) passes through the gap 40 without passing through the permanent magnet 12 and forms a magnetic circuit. That is, in general, the permeability of air constituting the gap 40 is substantially equal to the permeability of the permanent magnet 12 made of a rare earth magnet, a ferrite magnet, or the like, and therefore the gap length L2 of the gap 40 is smaller than the thickness t1 of the permanent magnet 12. When set, the magnetic resistance of the air gap 40 becomes smaller than the magnetic resistance of the permanent magnet 12. Thereby, when the magnetic field generated from the coil 14 wound around the first portion 16a of the substantially L-shaped portion 16 flows from the first portion 16a to the second portion 16b side, the magnetic field is on the permanent magnet 12 side. Without flowing to the gap 40 side.

Further, in the first embodiment, as shown in FIG. 3, the gap length L2 of the gap 40 is set such that the magnetic field generated from the coil 14 (see the one-dot chain line in FIG. 3) and the magnetic field generated from the permanent magnet 12 (two in FIG. 3). It is set to be larger than the total (2 × L1) of the gap lengths L1 of the two gaps 30 through which the dotted line (see FIG. 2) passes. Thereby, the magnetic field generated from the permanent magnet 12 passes through the air gap 30 without passing through the air gap 40 to form a magnetic circuit. That is, since the air gap 40 and the air gap 30 are composed of air having the same magnetic permeability, if the gap length L2 of the air gap 40 is set to be larger than twice the gap length L1 of the air gap 30, the air gap 40 The magnetic resistance is larger than the total magnetic resistance of the two gaps 30. Thereby, when the magnetic field generated from the permanent magnet 12 flows to the second portion 16b side of the substantially L-shaped portion 16, the magnetic field does not flow to the gap 40 side and passes through the first portion 16a. Flows to the side.

In the first embodiment, as shown in FIG. 3, the magnetic field generated from the coil 14 (see the alternate long and short dash line in FIG. 3) passes through the rotating shaft 21 and the magnetic field generated from the permanent magnet 12 (FIG. 3). The regions where the two-dot chain line) passes through the rotation shaft 21 are substantially coincident with each other.

In the first embodiment, as described above, the gap 40 disposed in the path through which the magnetic field generated from the coil 14 of the electromagnet 11 (see the alternate long and short dash line in FIG. 3) passes is provided in the electromagnet core 13. The permanent magnet 12 is disposed in a portion corresponding to the gap 40 of the electromagnet core 13 so that the generated magnetic field (see the two-dot chain line in FIG. 3) does not pass through the gap 40. Thereby, the magnetic field generated from the coil 14 passes through the gap 40 without passing through the permanent magnet 12 to form a magnetic circuit, so that the magnetic circuit formed by the magnetic field generated from the coil 14 is combined with the permanent magnet 12. Never cross. As a result, since the magnetic field generated from the coil 14 is not applied to the permanent magnet 12 in the direction opposite to the magnetization direction of the permanent magnet 12, the occurrence of irreversible demagnetization of the permanent magnet 12 can be suppressed. it can.

In the first embodiment, as described above, the air gap 40 is configured to have a magnetic resistance smaller than the magnetic resistance of the permanent magnet 12. Thereby, the magnetic field (refer to the one-dot chain line in FIG. 3) generated from the coil 14 of the electromagnet 11 can be easily flowed not to the permanent magnet 12 side but to the gap 40 side.

In the first embodiment, as described above, the gap 40 is formed so as to have a gap length L1 (see FIG. 3) smaller than the thickness t1 (see FIG. 3) of the permanent magnet 12. Thereby, the magnetic resistance of the air gap 40 can be easily made smaller than the magnetic resistance of the permanent magnet 12.

In the first embodiment, as described above, a gap length L2 (2 × L1) larger than twice the gap length L1 (see FIG. 3) of the gap 30 between the electromagnet core 13 and the rotating shaft 21 (see FIG. 3). The void 40 is formed so as to have (see FIG. 3). Thereby, since the magnetic resistance of the air gap 40 can be made larger than the total magnetic resistance of the air gaps 30 at two locations, the magnetic field generated from the permanent magnet 12 (see the two-dot chain line in FIG. 3) can be easily generated. It can flow not to the 40 side but to the gap 30 side.

Moreover, in 1st Embodiment, as mentioned above, it generate | occur | produces from the coil 14 of the electromagnet 11 so that the substantially U-shaped part 15 of the electromagnet core 13 may be isolate | separated into a pair of substantially L-shaped part 16 completely. The air gap 40 is formed so as to extend along the direction (radial direction) intersecting the magnetic field (see the dashed line in FIG. 3). Here, when the pair of substantially L-shaped portions 16 facing each other through the gap 40 are connected in part, magnetic flux leakage of the permanent magnet 12 occurs through the connected portions. The amount of magnetic flux passing through the gap 30 from the permanent magnet 12 is reduced. On the other hand, in the first embodiment, since the substantially U-shaped portion 15 is completely separated into the pair of substantially L-shaped portions 16 by the gap 40, the magnetic flux leakage of the permanent magnet 12 occurs. Since it can suppress, it can suppress that the quantity of the magnetic flux which passes the space | gap 30 from the permanent magnet 12 reduces.

In the first embodiment, as described above, the permanent magnet 12 is disposed across the pair of substantially L-shaped portions 16. Thereby, since a pair of substantially L-shaped part 16 separated completely is joined via permanent magnet 12, intensity of electromagnet core 13 containing a pair of approximately L-shaped part 16 can be raised. .

In the first embodiment, as described above, the vicinity of the surface 12a of the permanent magnet 12 on the side of the pair of substantially L-shaped portions 16 is divided between one side and the other side of the pair of substantially L-shaped portions 16. The magnets are magnetized so as to have different polarities (N polarity or S polarity), and a pair of substantially L of the permanent magnet 12 is disposed in the vicinity of the surface 12b opposite to the pair of substantially L-shaped portions 16 of the permanent magnet 12. Magnetization is performed so as to have a polarity opposite to the vicinity of the surface 12a on the side of the letter-shaped portion 16 side. As a result, the magnetic field entering and exiting the surface 12a of the permanent magnet 12 on the side of the pair of substantially L-shaped portions 16 and the surface 12b on the opposite side of the pair of substantially L-shaped portions 16 of the permanent magnet 12 can be obtained. The entrance / exit directions can be easily changed between one side and the other side of the pair of substantially L-shaped portions 16. As a result, the magnetic field generated by the permanent magnet 12 (see the two-dot chain line in FIG. 3) can be smoothly flowed from one side to the other side of the pair of substantially L-shaped portions 16 or from the other side to the one side. it can.

In the first embodiment, as described above, the yoke 17 that covers the surface of the permanent magnet 12 opposite to the pair of substantially L-shaped portions 16 is provided. Accordingly, the magnetic field generated from the surface of the permanent magnet 12 on the side opposite to the pair of substantially L-shaped portions 16 can be prevented from leaking into the air by the yoke 17.

In the first embodiment, as described above, the magnetic field generated from the coil 14 of the electromagnet 11 (see the one-dot chain line in FIG. 3) passes through the rotating shaft 21 and the magnetic field generated from the permanent magnet 12 (FIG. 3). The magnetic bearing 10 is configured so that the regions passing through the rotating shaft 21 substantially coincide with each other. Thereby, since the area | region of the rotating shaft 21 in which the magnetic attraction force by the electromagnet 11 and the permanent magnet 12 generate | occur | produces can be substantially corresponded, control of the support force (magnetic attraction force) for supporting the rotating shaft 21 non-contactingly. Can be easily performed.

In the first embodiment, as described above, the flat surface 16c is provided on the surface of the portion corresponding to the gap 40 of the electromagnet core 13, and the permanent magnet 12 is disposed on the flat surface 16c. Thereby, the permanent magnet 12 can be attached to the electromagnet core 13 in a stable state by the flat surface 16c.

In the first embodiment, as described above, the electromagnet core 13 having the gap 40 is arranged so as to surround the outer peripheral surface of the rotating shaft 21, and the electromagnet 11 and the permanent magnet 12 intersect the rotating shaft 21. By generating a magnetic field (see the alternate long and short dash line in FIG. 3) in a plane extending along the radial direction of the rotating shaft 21, the rotating shaft 21 is supported in the radial direction in a non-contact manner by a magnetic attractive force. Constitute. Here, in general, in a magnetic bearing, in order to prevent the rotating shaft from being deformed by the magnetic attractive force of the electromagnet and the permanent magnet, the axial length of the portion of the rotating shaft that is supported in a non-contact manner by the electromagnet and the permanent magnet. It is preferable to shorten the length (the length in the axial direction of the region of the rotating shaft through which the magnetic field generated from the electromagnet and the permanent magnet passes). In this case, in the first embodiment, the electromagnet 11 and the permanent magnet 12 are configured so as to generate a magnetic field in a plane intersecting the rotation axis 21 (in a plane orthogonal to the axial direction). Compared to the case where the electromagnet 11 and the permanent magnet 12 are configured to generate a magnetic field in a plane along the axis (in a plane along the axial direction), the rotation shaft is supported by the electromagnet 11 and the permanent magnet 12 in a non-contact manner. The length in the axial direction of the portion 21 (the length in the axial direction of the region of the rotating shaft 21 through which the magnetic field generated from the electromagnet 11 and the permanent magnet 12 passes) can be shortened. Thereby, it can suppress that the rotating shaft 21 deform | transforms with the magnetic attraction force of the electromagnet 11 and the permanent magnet 12. FIG.

In the first embodiment, as described above, the pair of substantially L-shaped portions 16 having the first portions 16 a extending in the radial direction are arranged to face each other with the gap 40 therebetween. The electromagnet core 13 is configured so as to include the substantially U-shaped portion 15. Thereby, the magnetic circuit (refer to the one-dot chain line in FIG. 3) generated from the coil 14 of the electromagnet 11 flows along the substantially U-shaped portion 15 of the electromagnet core 13, thereby passing the rotating shaft 21. Can be configured easily. As a result, a support force (magnetic attraction force) for supporting the rotating shaft 21 can be easily generated.

Also, in the first embodiment, as described above, a pair of substantially U-shaped portions 15 are provided so as to sandwich the rotating shaft 21 from both sides in the radial direction. Thereby, since the magnetic attraction force by the pair of substantially U-shaped portions 15 acts only in the direction in which the rotating shaft 21 is sandwiched, the magnetic attraction force in the direction in which the rotating shaft 21 is sandwiched can be easily controlled.

(Second Embodiment)
Next, with reference to FIG. 4, the magnetic bearing 110 by 2nd Embodiment of this invention is demonstrated. In the second embodiment, an example will be described in which the electromagnet core 113 includes four substantially T-shaped portions 115, unlike the first embodiment in which the electromagnet core 13 includes four approximately U-shaped portions 15.

In the second embodiment, as shown in FIG. 4, the electromagnet core 113 is composed of four substantially T-shaped portions 115 arranged so as to surround the outer peripheral surface of the rotating shaft 21 in a circumferential shape. These four substantially T-shaped portions 115 are arranged so as to be adjacent to each other along the circumferential direction via the gap 40a. In addition, the electromagnet core comprised by the several electromagnet core which has such a substantially T shape integrally couple | bonded along the circumferential direction (The several substantially T-shaped part adjacent along the circumferential direction) Conventionally, an electromagnet core having no gap between them has been generally used.

Here, each of the four substantially T-shaped portions 115 extends to both sides in the circumferential direction from a first portion 115a extending along the radial direction and an end portion of the first portion 115a opposite to the rotating shaft 21. And a second portion 115b. The coil 14 is wound around the first portion 115a. In addition, a flat surface 115c is provided on the surface of the second portion 115b opposite to the rotation shaft 21. And the permanent magnet 12 is arrange | positioned ranging over the two flat surfaces 115c provided in the 2nd part 115b of the two adjacent substantially T-shaped parts 115. FIG. A yoke 17 is bonded to the surface 12 b of the permanent magnet 12 on the side opposite to the substantially T-shaped portion 115.

Thereby, in 2nd Embodiment, the magnetic field (refer the dashed-dotted line of FIG. 4) which generate | occur | produces from the coil 14 does not pass the permanent magnet 12, but the 1st part 115a and 2nd part 115b which adjoin the circumferential direction, air gap | interval The magnetic circuit is configured to pass through 30a (the space between the second portion 115b and the rotary shaft 21), the gap 40, and the rotary shaft 21. Further, the magnetic field generated by the permanent magnet 12 (see the two-dot chain line in FIG. 4) passes through the first portion 115a and the second portion 115b, the gap 30a, and the rotating shaft 21 adjacent in the circumferential direction without passing through the gap 40a. Pass through to form a magnetic circuit.

Also in the second embodiment, similarly to the first embodiment, the gap length L2a of the gap 40a provided in the electromagnet core 113 is smaller than the thickness t1 (see FIG. 4) of the permanent magnet 12, and the electromagnet It is set larger than the total (2 × L1a) of the gap length L1a (see FIG. 4) of the two gaps 30a between the core 113 and the rotating shaft 21.

In the second embodiment, as described above, the electromagnet core 113 is separated from the first portion 115a extending along the radial direction and the end of the first portion 115a extending along the radial direction on the side opposite to the rotating shaft 21. A substantially T-shaped portion 115 having second portions 115b extending on both sides in the circumferential direction is included. Then, four substantially T-shaped portions 115 are provided so as to be adjacent to each other along the circumferential direction via the gap 40. Thus, an electromagnet core that has been generally used conventionally (an electromagnet core that is configured by integrally joining a plurality of electromagnet cores having a substantially T-shape along the circumferential direction (along the circumferential direction). It is possible to easily suppress the occurrence of irreversible demagnetization of the permanent magnet 12 by the air gap 40 simply by providing the air gap 40 in the electromagnet core having no air gap between a plurality of adjacent substantially T-shaped portions)). Thus, an electromagnet core 113 capable of supporting the above can be configured.

In addition, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

For example, in the first and second embodiments described above, an example in which a gap made of air is used as the magnetoresistance change portion of the present invention is shown, but the present invention is not limited to this. In the present invention, a mold resin may be used as the magnetoresistance change portion. That is, the air gaps of the first and second embodiments may be filled with a mold resin having a magnetic resistance smaller than that of the permanent magnet. In this case, if the magnetic path length of the mold resin is smaller than the thickness of the permanent magnet and larger than the gap length of the gap between the electromagnet core and the rotating shaft, the magnetic resistance of the mold resin can be easily increased. It can be made smaller than the magnetic resistance of the permanent magnet.

Moreover, in the said 1st and 2nd embodiment, the example which has arrange | positioned the permanent magnet on the flat surface (radial direction end surface) provided in the surface on the opposite side to the rotating shaft of the part corresponding to the space | gap of an electromagnet core is shown. However, the present invention is not limited to this. In this invention, you may arrange | position a permanent magnet on the axial direction end surface orthogonal to the radial direction end surface of the part corresponding to the space | gap of an electromagnet core.

In the first embodiment, as shown in FIG. 3, the gap length L2 of the air gap 40 is equal on the rotating shaft 21 side and the permanent magnet 12 side. However, the present invention is not limited to this. In the present invention, as in the first modification shown in FIG. 5, the gap length of the air gap 41 may be different between the rotating shaft 21 side and the permanent magnet 12 side. The air gap 41 is an example of the “magnetic resistance changing portion” in the present invention.

As shown in FIG. 5, in the first modification, the gap 41 is formed so that the gap length gradually increases from the rotating shaft 21 side toward the permanent magnet 12 side. That is, the end surfaces of the pair of substantially L-shaped portions 216 facing each other through the gap 41 are formed so as to be gradually separated from the rotating shaft 21 side toward the permanent magnet 12 side. Here, in the first modification, the average gap length L3 of the air gap 41 (the average of the gap length L4 at the end portion on the rotating shaft 21 side and the gap length L5 at the end portion on the permanent magnet 12 side) is The thickness is set to be smaller than the thickness t1 and larger than the total (2 × L1) of the gap length L1 of the two gaps 30 between the electromagnet core 213 and the rotating shaft 21. The substantially L-shaped portion 216 is an example of the “core portion” in the present invention.

In the first modification, as described above, the gap length L5 of the end portion of the air gap 41 on the permanent magnet 12 side is larger than the gap length L4 of the end portion on the rotating shaft 21 side, so that the magnetic field generated from the permanent magnet 12 is Further, it is possible to further suppress leakage through the portion of the air gap 41 on the permanent magnet 12 side without passing through the air gap 30.

In the first embodiment, as shown in FIGS. 2 and 3, the example in which the gap 40 for completely separating the electromagnet core 13 is provided is shown, but the present invention is not limited to this. In this invention, you may provide the space | gap which isolate | separates substantially, without separating an electromagnet core completely. For example, as in the second, third, and fourth modifications shown in FIGS. 6, 7, and 8, respectively, the

electromagnet cores

313a, 313b, and 313c are connected by the

thin portions

18a, 18b, and 18c.

Such voids

42a, 42b and 42c may be provided. The air gaps 42a to 42c are examples of the “magnetic resistance changing portion” in the present invention.

As shown in FIG. 6, in the second modified example, the opposed end surfaces of the pair of substantially L-shaped portions 316a opposed via the gap 42a are connected to each other by the narrow portion 18a at the end on the permanent magnet 12 side. ing. Further, as shown in FIG. 7, in the third modified example, the opposing end surfaces of the pair of substantially L-shaped portions 316 b that are opposed to each other through the gap 42 b are mutually connected by the narrow portion 18 b at the end on the rotating shaft 21 side. It is connected. Further, as shown in FIG. 8, in the fourth modification, the opposing end surfaces of the pair of substantially L-shaped portions 316 c that are opposed via the gap 42 c are the end portions on the permanent magnet 12 side and the rotating shaft 21 side. Both ends are connected to each other by a thin portion 18c. Here, in the second, third, and fourth modified examples, the thickness of the

thin portions

18a, 18b, and 18c is used in order to suppress the magnetic flux leakage of the permanent magnet 12 through the

thin portions

18a, 18b, and 18c. It is preferable that t3 (see FIG. 6), t4 (see FIG. 7), and t5 (see FIG. 8) be thinned to the processing limit of the steel plate. The substantially L-shaped portions 316a to 316c are examples of the “core portion” in the present invention.

In the second to fourth modifications, as described above, the gaps 42a to 42c are provided so that the electromagnet cores 313a to 313c are connected by the thin portions 18a to 18c. As a result, the pair of substantially L-shaped portions 316a to 316c constituting the electromagnet cores 313a to 313c are integrally connected to each other by the thin portions 18a to 18c. Electromagnet cores 313a to 313c can be manufactured as parts, and the number of parts can be reduced.

Moreover, in the said 1st Embodiment, as shown in FIG. 3, the surface 12a vicinity of the pair of substantially L-shaped part 16 side of the permanent magnet 12, and a pair of substantially L-shaped part 16 of the permanent magnet 12 and Shows an example in which both the vicinity of the surface 12b on the opposite side is magnetized so as to have N polarity or S polarity, but the present invention is not limited to this. In the present invention, as in the fifth modification shown in FIG. 9, only the vicinity of the surface 112 a on the side of the pair of substantially L-shaped portions 16 of the permanent magnet 112 is arranged on one side of the pair of substantially L-shaped portions 16. And the other side may be magnetized so as to have different polarities (N polarity and S polarity).

As shown in FIG. 9, in the fifth modification, the permanent magnet 112 is disposed over the flat surface 16 c provided in the pair of substantially L-shaped portions 16. The vicinity of the surface 112a on the side of the pair of substantially L-shaped portions 16 of the permanent magnet 112 is magnetized so as to have S polarity in the left region of FIG. 9, and N polarity in the right region of FIG. It is magnetized to have

In the fifth modified example, as described above, only the vicinity of the surface 112a of the permanent magnet 112 on the side of the pair of substantially L-shaped portions 16 is magnetized. Thereby, both the vicinity of the surface 12a on the side of the pair of substantially L-shaped portions 16 of the permanent magnet 12 and the vicinity of the surface 12b on the side opposite to the pair of substantially L-shaped portions 16 of the permanent magnet 12 are magnetized. Unlike the above-described first embodiment (see FIG. 3), a member (on the surface 112b opposite to the pair of substantially L-shaped portions 16 of the permanent magnet 112, which becomes a path of a magnetic field generated from the permanent magnet 112) Since it is not necessary to provide a member corresponding to the yoke 17 of the first embodiment, the number of parts can be reduced.

Moreover, in the said 1st Embodiment, as shown in FIG.2 and FIG.3, although the yoke 17 and the pair of substantially L-shaped part 16 were shown as another components, this invention is shown to this. Not exclusively. In the present invention, as in the sixth modification shown in FIG. 10, the yoke 417 and the pair of substantially L-shaped portions 416 may be provided as an integral part.

As shown in FIG. 10, in the sixth modification, both end portions of the yoke 417 of the electromagnet core 413 in the left-right direction and the pair of substantially L-shaped portions 416 of the electromagnet core 413 are formed by the thin-walled connecting portion 19. Are connected to each other. The connecting portion 19 is provided so as to cover both end surfaces of the permanent magnet 12 in the left-right direction. Here, in the sixth modification, in order to suppress the occurrence of magnetic flux leakage of the permanent magnet 12 through the connecting portion 19, the thickness t6 (see FIG. 10) of the connecting portion 19 is reduced to the processing limit of the steel plate. It is preferable to do this. The substantially L-shaped portion 416 is an example of the “core portion” in the present invention.

In the sixth modified example, as described above, the yoke 417 and the pair of substantially L-shaped portions 416 of the electromagnet core 413 are connected to each other by the thin connecting portion 19. As a result, the yoke 417 and the pair of substantially L-shaped portions 416 can be manufactured as an integral part that can be easily manufactured by processing a steel plate, and the number of parts can be reduced.

Moreover, in the said 1st Embodiment, as shown in FIG.2 and FIG.3, although the example which provided the one permanent magnet 12 so that a pair of substantially L-shaped part 16 might be straddled was shown, this invention is this. Not limited to. In the present invention, as in the seventh modification shown in FIG. 11, two

permanent magnets

212a and 212b may be provided so as to correspond to each of the pair of substantially L-shaped portions 16.

As shown in FIG. 11, in the sixth modification, the permanent magnet 212a is disposed on the flat surface 16c of the substantially L-shaped portion 16 disposed on the left side of FIG. The permanent magnet 212a is magnetized so that the vicinity of the surface on the substantially L-shaped portion 16 side has S polarity, and is magnetized so that the vicinity of the surface on the yoke 17 side has N polarity. Further, in the sixth modification, the permanent magnet 212b is disposed on the flat surface 16c of the substantially L-shaped portion 16 disposed on the right side of FIG. The permanent magnet 212b is magnetized so that the vicinity of the surface on the substantially L-shaped portion 16 side has N polarity, and the vicinity of the surface on the yoke 17 side is magnetized so as to have S polarity.

Moreover, in the said 1st Embodiment, as shown in FIG. 1, although the example which applies this invention to the magnetic bearing 10 which supports the rotating shaft 21 non-contacting in a radial direction was shown, 8th deformation | transformation shown in FIG. As an example, the present invention is also applicable to the magnetic bearing 510 that supports the rotating shaft 21 in the axial direction in a non-contact manner.

As shown in FIG. 12, in the eighth modification, a pair of magnetic bearings 510 including an electromagnet 511 including an electromagnet core 513 and a coil 514 and a permanent magnet 512 are provided on both sides in the radial direction of the rotary shaft 21. . Each of the pair of magnetic bearings 510 is provided so as to sandwich the plate-like member 22 that intersects the rotating shaft 21 from both sides in the axial direction. In the eighth modified example, both the electromagnet 511 and the permanent magnet 512 are rotated by a magnetic attractive force by generating a magnetic field (refer to a one-dot chain line and a two-dot chain line in FIG. 12) in a plane along the rotation axis 21. The shaft 21 is configured to be supported in a non-contact manner in the axial direction. The plate-like member 22 is an example of the “rotary shaft portion” in the present invention.

Here, in the eighth modification, the electromagnet core 513 of the electromagnet 111 is provided with a gap 40b through which a magnetic field generated from the coil 514 of the electromagnet 511 (see the dashed line in FIG. 12) passes. And the permanent magnet 512 is arrange | positioned in the part corresponding to the space | gap 40b of the electromagnet core 513 so that the magnetic field (refer to the dashed-two dotted line of FIG. 12) which generate | occur | produces from the permanent magnet 512 may not pass the space | gap 40b. A yoke 517 is provided on the surface of the permanent magnet 512 opposite to the electromagnet core 513. The air gap 40b is an example of the “magnetic resistance changing portion” in the present invention.

Also in the eighth modification, as in the first embodiment, the gap length L2b of the gap 40b provided in the electromagnet core 513 is smaller than the thickness t7 (see FIG. 12) of the permanent magnet 512, and the electromagnet The gap length L1b (see FIG. 12) of the two gaps 30b between the core 513 and the rotating shaft 21 is set to be larger than the sum (2 × L1b).

Claims

Electromagnets (11, 511) including electromagnet cores (13, 113, 213, 313a, 313b, 313c, 413, 513) and coils (14, 514);
A permanent magnet (12, 112, 212a, 212b) that is attached to the electromagnet core and supports the rotating shaft portion (21, 22) in a non-contact manner by a magnetic attractive force together with the electromagnet;
The electromagnet core has a magnetoresistive change portion (40, 40a, 40b, 41, 42a, 42b, 42c) disposed in a path through which a magnetic field generated from the coil of the electromagnet passes.
The said permanent magnet is a magnetic bearing arrange | positioned in the part corresponding to the said magnetoresistive change part of the said electromagnet core so that the magnetic field generated from the said permanent magnet may not pass through the said magnetoresistive change part.
The magnetic bearing according to claim 1, wherein the magnetoresistive change portion has a magnetic resistance smaller than a magnetic resistance of the permanent magnet.
The magnetic bearing according to claim 1, wherein the magnetoresistive change portion has a magnetic path length smaller than a thickness of the permanent magnet.
The magnetoresistance change portion has a magnetic path larger than a gap length of a portion (30, 30a, 30b) through which a magnetic field generated from the coil and the permanent magnet in a space between the electromagnet core and the rotating shaft portion passes. The magnetic bearing according to claim 1, wherein the magnetic bearing has a length.
The magnetoresistive change unit is arranged along a direction intersecting a magnetic field generated from the coil so as to substantially separate the electromagnet core into a pair of core portions (16, 216, 316a, 316b, 316c, 416). The magnetic bearing according to claim 1, wherein the magnetic bearing is extended.
The magnetic bearing according to claim 5, wherein the permanent magnet is disposed across the pair of core portions.
The magnetoresistive change portion is a gap (40, 41, 43) that completely separates the electromagnet core or a gap (42a, 42b, 42c) that connects the electromagnet core at a thin portion. The magnetic bearing according to claim 6.
The magnetic bearing according to claim 6, wherein at least the surface vicinity of the pair of core portions of the permanent magnet is magnetized to have different polarities on one side and the other side of the pair of core portions. .
The surface (12a) vicinity of the pair of core parts side of the permanent magnet is magnetized so as to have different polarities on one side and the other side of the pair of core parts,
The vicinity of the surface (12b) opposite to the pair of core portions of the permanent magnet is magnetized so as to have a polarity opposite to that of the vicinity of the surface of the pair of core portions of the permanent magnet. Item 9. A magnetic bearing according to Item 8.
The magnetic bearing according to claim 9, further comprising a yoke (17, 417, 517) covering a surface of the permanent magnet opposite to the pair of core portions.
The magnetic bearing according to claim 10, wherein the yoke and the pair of core portions are connected to each other by a thin connecting portion (19).
The magnetic bearing according to claim 5, wherein a pair of the permanent magnets is provided so as to correspond to each of the pair of core portions.
The region in which the magnetic field generated from the coil passes through the rotating shaft portion and the region in which the magnetic field generated from the permanent magnet passes through the rotating shaft portion substantially coincide with each other. The magnetic bearing described.
The surface of the portion of the electromagnet core corresponding to the magnetoresistance change portion includes a flat surface (16c, 115c),
The magnetic bearing according to claim 1, wherein the permanent magnet is disposed on the flat surface of a portion corresponding to the magnetoresistance change portion of the electromagnet core.
The electromagnet core having the magnetoresistive change portion is disposed so as to surround an outer peripheral surface of the rotating shaft portion,
The electromagnet and the permanent magnet generate a magnetic field in a plane that intersects the rotating shaft portion and extends along the radial direction of the rotating shaft portion, thereby causing the rotating shaft portion to be non-radially formed by a magnetic attraction force. The magnetic bearing according to claim 1, wherein the magnetic bearing is configured to be supported by contact.
The electromagnet core has a pair of substantially L-shaped portions (16, 216, 316a, 316b, 316c, 416) having a portion (16a) extending along the radial direction in the circumferential direction via the magnetoresistive change portion. The magnetic bearing according to claim 15, comprising a substantially U-shaped part configured by being arranged adjacent to each other.
The magnetic bearing according to claim 16, wherein at least a pair of the substantially U-shaped portions are provided so as to sandwich the rotating shaft portion from both sides in the radial direction.
The electromagnet core has a portion (115a) extending along the radial direction and a portion (115b) extending on both sides in the circumferential direction from an end of the portion extending along the radial direction opposite to the rotation shaft portion. A substantially T-shaped portion (115) having
The magnetic bearing according to claim 15, wherein a plurality of the substantially T-shaped portions are provided so as to be adjacent along a circumferential direction via the magnetoresistive change portion.
19. The magnetic bearing according to claim 18, wherein four substantially T-shaped portions are provided so as to be adjacent along the circumferential direction via the magnetoresistive change portion.
The rotating shaft portion includes a rotating shaft (21) and a plate-like member (22) intersecting with the rotating shaft,
The electromagnet core having the magnetoresistive change portion is disposed so as to sandwich the plate-like member from both sides in the axial direction of the rotating shaft,
The electromagnet and the permanent magnet support the rotary shaft portion in a non-contact manner in the axial direction of the rotary shaft by supporting the plate member in a non-contact manner in the axial direction of the rotary shaft by a magnetic attraction force. The magnetic bearing according to claim 1, which is configured as follows.